CHEAP AND NASTY OIL

NZ Truth, Issue 1197, 8 November 1928, Page 21

CHEAP AND NASTY OIL

I Is T66 Dfiar At Half the Price

TCONOMY m, dealing with the motor engine can be a waste. Many people make tlie; mistake of buying cheap oil, which is obtainable m a^ about half ithe price of well-l^own oils. ;; ; ; . .

SOME of , o these cheap oils-ire-rebpon-siblefor a\great deal bf.damjageto ; engines, resulting m heavy carbonisation and. valve-pitting. . > . - • ! at' is. the .gummy, elements,, m: oil which causes carbon.' v Low grade thick oil is oil !p .which these substances have not been removed, and' the appearance .of .body vis fictitious* •..". /-.' '■ ■ , \ The gummy substances user ful ■ service' as regards "lubrication. . , ■ Underthe violent motions -of' 'the l pistons' and the terrific heat of. -the > gases as .they /explode, they decompose and form hard carbon ■ 6n'v;the;-tbp 'of \the pistons and cylinder heads, \andf on:. the faces and stems of. the. valye^.. .; ';'"?. As soon as sufficient^ carbon is /deposited, which is not long:' m the .case of bad oil, it.beconies ihcandesqeht under heat and^ causes pre-ignition.

. 'lt also breaks off. m lumps and falls on :to the moving surfaces, causing wear. ■' '"' V: • It is' forced into the grooves of the piston' r^ngs, and renders the rings immbyabljJafixed and- useless after holding, compression. ! Carbon under the valve seats prevents a gas tight seal, and thus power is lost, „. v . ■;. • ■■• -In, addition,, the seating of the „ valye's .', becomes ' burnt, and the . . valves themselves are quickly '-'■" ruined... Another point is that bad , oil does not last as long as good '■.■oil. .;.-.•.;•-.•■• . " ' ' . ~ Dilution^ of petrol is far - more serious with poor grade lubricant than it Is , with oir of, first quality. . . ] It can be seen, therefore,' that the use of cheap oil confers no saving.